1. Field of the Invention
The present invention relates to a mechanical technology used in the treatment for various kinds of fluids such as, for example, a compressive fluid, a non-compressive fluid and the like, and more particularly, to a fluid flowing control device comprising a valve having fluid flowing paths which are devised in a more sophisticated configuration by controlling fluid resistance, back pressure and overall operations and by controlling the velocity of fluid by the maximal use of available volume to thereby prevent the generation of cavitation, flashing, blocking by foreign materials, and the damage of internal parts.
The present invention is related to a fluid flowing resistor, a back pressure control part and can be applied to a multi-orifice type valve, a multi-path type valve, or any fluid flowing control device which is similar thereto.
2. The Prior Art
Conventionally, the devices, which are related to valves and resistors, are applied in a wide range of fields, in which some are commonly called a xe2x80x98multi-path type valvexe2x80x99.
Specifically, a conventional multi-path type valve is applied in an ultimate situation or in a field where a high degree of precise control should be required.
Moreover, the velocity control for a fluid can be achieved in the multi-path type valve, and therefore, the valve can be applied in all devices where a long life period and a good quality of performance of the valve should be satisfied.
The conventional multi-path type valve can be applied in fields where noise and cavitation are controlled or in a high precision control field where hydraulic fluid or non-hydraulic fluid is adjusted. In addition, the valve is applied in various industrial fields containing thermal power generation, nuclear power generation, petrochemical production, refining and various chemical processes and so on.
A fluid flowing resistor of the conventional multi-path type valve, which is applied in the various fields as discussed above, is based upon a series of discs or cylinders which are stacked or overlapped over one another.
Each disc or cylinder has a plurality of separated paths and tortuous paths formed thereon, each of which is adapted to control pressure or an amount of fluid flow of the devices over the whole length of the valve. The details of devices concerning the above mentioned can be shown in U.S. Pat. Nos. 4,921,014, 4,567,915, 4,407,327 and 4,105,048.
As shown in the prior art, the fluid passing through the tortuous paths experiences velocity head loss.
The discharging velocity of the fluid is controlled so as to be decreased, such that the resistance created in the fluid flowing path under certain conditions reduces the cavitation, corrosion, abrasion, noise and vibration generated due to the high pressure of the fluid flow.
The conventional multi-path type of valve and fluid flow resistor are characterized in that the internal disc or cylinder forms a directional path and a winding turn type path therein.
A plug is adapted to move up and down on the inside of the conventional cage and has the leading end for opening/closing the fluid flowing paths of the fluid flowing resistor to adjust the overall flow of the fluid passing through the valve and for sealing the flow of the fluid, while being in contract with a seat.
In any case, for the purpose of performing the up and down movement of the plug in a stable manner and contacting the plug with the seat in a concentric axis, a labyrinth plug is used, which has a plurality of circumferential grooves on the lower portion of the plug.
In the conventional cage for utilizing as a valve, the size of the cage becomes bulky because of the small fluid flowing path and the simple tortuous path formation for generating the required amount of velocity head loss.
Moreover, this yields the following: a) the total size of the valve becomes large; b) the whole materials required for the valve are added; and c) the installation space of the valve is enlarged.
In addition, a vena contracta phenomenon caused by an orifice principle occurs in the vicinity of the sealing portion thereof or a clearance resulting in the cavitation, flashing, erosion/corrosion, noise and vibration caused due to velocity increment of fluid flow and decrement of the pressure on the fluid flowing resistor, plug, seat and the like.
In the same manner as the above, these phenomena occur even on the labyrinth plug.
On the other hand, since the cage comprises a plurality of fluid flowing paths having the sectional area so as to generate the desired amount of velocity head loss if foreign materials are inserted into the inlet of the valve, the paths of the cage or the inlet thereof are blocked which thereby deteriorates the inherent performance of the valve. Meanwhile, in the valve where the fluid passes through the cage from the lower portion of the plug, the sealing portion of the leading end of the plug, which is moved in an axial direction, is damaged due to the foreign materials blocking up the inlet of the path of the cage, to drastically deteriorate the sealing function of the valve.
In this case, so as to filter the foreign materials passing into the inlet of the valve, a separate screen is generally attached on the inlet for flowing the fluid to the valve.
An object of the present invention is to provide a fluid flowing control device comprising a valve which can be assembled and fabricated in an easy and simple manner, while retaining the characteristics of a cage of a multi-path type valve, and which can allow the fluid flowing resistor as a cage to restrict the insertion of foreign materials and form a predetermined space between a plug and the fluid flowing resistor, to thereby prevent the fluid flowing resistor from being blocked by the materials as well as to prevent the interaction of the foreign materials with the plug, without having a separate screen on the inlet for flowing the fluid in the valve.
Another object of the present invention is to provide a fluid flowing control device comprising a valve which can generate a large amount of velocity head loss on a plurality of fluid flowing paths to thereby increase a tortuous section per the fluid flowing path under the constant pressure drop, whereby the fluid flowing path is not blocked by the foreign materials passing through the valve to thereby increase an amount of the fluid flow within a predetermined volume thereof.
Still another object of the present invention is to provide a fluid flowing control device comprising a valve which can perform a structural separation and fluid dispersion in a device which interacts with the fluid flow to thereby prevent a vena contracta phenomenon in the vicinity of the fluid terminating stop position where a high pressure difference is generated, whereby cavitation, flashing, erosion/corrosion, noise and vibration can not be generated on a fluid flowing resistor, plug and seat.
To achieve these and other objects according to the present invention, a fluid flowing control device of a valve having a body comprising a fluid inlet and fluid outlet, a plug moved between the fluid inlet and the fluid outlet to control fluid flow, and a cage having a plurality of holes and grooves, the plug being closely attached and movable on the inside of the cage, which includes: the cage having an inside cylinder which is adapted to be closely contacted with the plug and defines a plurality of holes and protrusions in axial and radial directions, respectively; an outside cylinder which defines a plurality of holes in axial and radial directions respectively; a first internal cylinder which is overlapped and coupled between the inside and outside cylinders and forms a plurality of concave/convex grooves having rectangular sectional elbows with a recess in an axial direction and defining a plurality of holes therein, a second internal cylinder which is coupled with the first internal cylinder and defines a plurality of holes in axial and radial directions and upper and lower supporting plates for closely coupling the inside and outside cylinders with the first and second internal cylinders on the top and bottom ends thereof; the plug forming a sealing portion and an opening/closing portion which are each in contact with a seat, on the leading end of the lower portion thereof and a plurality of holes connected to the opening/closing portion through a groove on the top portion of the opening/closing portion, to thereby open/close the seat and control the fluid flow, while being moved in the inside of the cage; and the seat being in internal-contact with the plug.